Objective lens holding device and usage thereof

Abstract

The present invention relates to an objective lens holding unit which allows for accurate information reading and writing. In order to make it possible for a read/write device including an objective lens with a small working distance, particularly such as a BD-compliant read/write device, to perform accurate information reading and writing, the objective lens holding unit of the present invention includes two ribs provided on a surface of a lens holder facing an optical disk, the lens holder holding an objective lens, so as to sandwich the objective lens therebetween. On the surfaces of the ribs facing the optical disk, protectors are provided so as to project toward the optical disk more than the objective lens does.

1 . An objective lens holding unit comprising: a lens holder which holds an objective lens so that the objective lens faces an optical storage medium, the objective lens converging light emitted from a light source onto the optical storage medium; and protectors which are provided so that surfaces of the protectors facing the optical storage medium are closer to the optical storage medium than the objective lens is, 
 wherein:    at least two ribs are provided on a surface of the lens holder facing the optical storage medium so as to sandwich the objective lens therebetween; and    the protectors are provided on surfaces of the ribs facing the optical storage medium.    
   
   
       2 . The objective lens holding unit according to  claim 1 , wherein: 
 the ribs are provided so that their longer sides are substantially perpendicular to a tangential direction to an outer edge of the optical storage medium.    
   
   
       3 . The objective lens holding unit according to  claim 1 , wherein: 
 the protectors are coating layers formed by coating.    
   
   
       4 . The objective lens holding unit according to  claim 1 , wherein: 
 the protectors are provided on both ends of longer sides of the ribs.    
   
   
       5 . The objective lens holding unit according to  claim 1 , wherein: 
 surfaces of the ribs facing the optical storage medium are provided between the objective lens and the optical storage medium.    
   
   
       6 . An objective lens driving unit comprising: 
 an objective lens holding unit including: a lens holder which holds an objective lens so that the objective lens faces an optical storage medium, the objective lens converging light emitted from a light source onto the optical storage medium; and protectors which are provided so that surfaces of the protectors facing the optical storage medium are closer to the optical storage medium than the objective lens is, wherein: at least two ribs are provided on a surface of the lens holder facing the optical storage medium so as to sandwich the objective lens therebetween; and the protectors are provided on surfaces of the ribs facing the optical storage medium;    a movable part which is supported so as to be movable in at least two directions, focusing direction and tracking direction, with respect to the optical storage medium; and    a driving section which causes the movable part to move in at least the two directions.    
   
   
       7 . An optical pickup device including an objective lens driving unit, 
 the objective lens driving unit comprising:    (i) an objective lens holding unit including: a lens holder which holds an objective lens so that the objective lens faces an optical storage medium, the objective lens converging light emitted from a light source onto the optical storage medium; and protectors which are provided so that surfaces of the protectors facing the optical storage medium are closer to the optical storage medium than the objective lens is, wherein: at least two ribs are provided on a surface of the lens holder facing the optical storage medium so as to sandwich the objective lens therebetween; and the protectors are provided on surfaces of the ribs facing the optical storage medium,    (ii) a movable part which is supported so as to be movable in at least two directions, focusing direction and tracking direction, with respect to the optical storage medium; and    (iii) a driving section which causes the movable part to move in at least the two directions.    
   
   
       8 . A read/write device including an optical pickup device, 
 the optical pickup device including an objective lens driving unit,    the objective lens driving unit comprising:    (i) an objective lens holding unit including: a lens holder which holds an objective lens so that the objective lens faces an optical storage medium, the objective lens converging light emitted from a light source onto the optical storage medium; and protectors which are provided so that surfaces of the protectors facing the optical storage medium are closer to the optical storage medium than the objective lens is, wherein: at least two ribs are provided on a surface of the lens holder facing the optical storage medium so as to sandwich the objective lens therebetween; and the protectors are provided on surfaces of the ribs facing the optical storage medium,    (ii) a movable part which is supported so as to be movable in at least two directions, focusing direction and tracking direction, with respect to the optical storage medium; and    (iii) a driving section which causes the movable part to move in at least the two directions.